Img-color-extractor NPM

img-color-extractor

Node module to extract REAL main colors from a PNG image

REAL mean that if #333333 and #669F64 are the most present colors in a picture, img-color-extractor will extract exactly #333333 and #669F64 and not some color between the two.

Installation

$ npm install --save img-color-extractor

##Usage

const fs = require('fs');
const colorExtractor = require('img-color-extractor');

stream = fs.createReadStream('/test/in.png')

defaultsOptions = {
    background: '#FFFFFF',
    alphaMin: 0,
    dist: 100,
    greyVa: -1,
};

// retun a promise resolving an array of objects as:
// [{ color: `hexa`, n: `numberOfOccurrence`, r: `ratio` }, ...]
colorExtractor.extract(stream, opts)
.then(colors => {
    console.log(colors) // [ { color: '#ffffff', n: 1515551, r: 0.728368706 },
                        //   { color: '#333333', n: 388783, r: 0.1868478003 },
                        //   { color: '#669f64', n: 174227, r: 0.0837329094 },
                        //   { color: '#b2ceb1', n: 2186, r: 0.0010505842 } ]
});

alt text

##Options

background background color if input has alpha layer. default to '#FFFFFF' (white)
alphaMin ignore all pixels with alpha layer under alphaMin. default to 0 0 keeps all, 256 or more removes all
dist distance for regrouping pixels by color. default to 100 distance is calculated as sqrt((r1 - r2)^2 + (g1 - g2)^2 + (b1 - b2)^2)`
greyVa ignore all pixels with variance(r, g, b) < greyVa. default to -1 useful to ignore shades of grey -1 keeps all, 14451 or more removes all